The proliferation of conventional wireless and computing devices in the recent past has been exceptional. These devices are capable of exchanging data and/or voice signals among each other and/or with a central location using radio waves over dedicated frequencies or dedicated segments of the electromagnetic spectrum. The speed and range of these wireless communications is limited by, among other things, interference and power limitations. There is an ongoing effort to overcome these issues and to make these wireless communications as fast as their wired cousins and to increase their effective range.
One of the ways to overcome the above mentioned issues is by utilizing smart antennas (xe2x80x9cSAsxe2x80x9d). Deploying the SAs in communication systems has several known benefits, e.g., extended range, higher capacity, interference mitigation, lower power, etc. When using the SAs in conjunction with multiple access wireless networks (e.g., IEEE 802.11b wireless standard) some form of collision avoidance is required. For example, when there is a directed-beam transmission to a target mobile unit (xe2x80x9cMUxe2x80x9d), it may not be heard by a neighboring MU. The neighboring MU then would mistakenly assume that the radio frequency or channel is free and attempt to access it, thereby, causing a collision with an ongoing transmission. One possible solution for this problem is to use the built-in Request to Send/Clear to Send (xe2x80x9cRTS/CTSxe2x80x9d) mechanism as described in the 802.11 standard. The RTS/CTS mechanism provides for a four-way handshake that results in higher overhead (e.g., two extra portions required to transmit one payload). There is a need for a system and method to eliminate this overhead without transmitting additional portions.
The present invention relates to a method and system for access control in a communication network which includes a first wireless unit, a second wireless unit and at least one further unit. The first unit generates a frame for the second unit. The frame includes a first portion and a second portion. The first portion includes data indicating that the first unit is about to establish a direct communication channel with the second unit. The first portion is transmitted to the second unit and is received by the at least one further wireless unit.
A direct communication channel is established between the first unit and the second unit for transmission of the second portion. During the transmission of the second portion, the at least one further unit abstains from communications using the direct communication channel.